The present invention departs from the tubular moisture-absorbing device disclosed in U.S. Pat. No. 5,676,739 (Gustafsson) designed for vertical disposition in, for instance, a closed steel container for transport of humidity-sensitive goods. The device is made of a polymer coated board which provides a required stiffness. Starting from its upper end, it comprises, in a longitudinal direction, a chamber with a moisture-absorbing material, such as calcium chloride, which forms an aqueous solution on contact with humid air. The salt solution is continuously drained into a lower liquid collection chamber provided in the form of a plastic container with which the upper chamber is in communication. The particulate desiccant material is retained in the upper chamber by a sieve means comprising a non-return valve. Contact of the desiccant with ambient air is ensured by a netting element located in front of an opening in the wall of the upper chamber. The netting element is designed to prevent the aqueous solution from leaving the upper chamber through it rather than through the sieve means.
While the moisture-absorbing device of Gustafsson has been shown to function well in industrial practice, there is room for improvement. Manufacture of the device of the '739 patent necessitates folding and longitudinal gluing of a sheet of plastic board to provide a tubular structure, manufacturing and attaching several plastic parts, such as the sieve means and the netting element, to the tubular structure by gluing, and attaching the plastic container forming the lower chamber to the sieve means, etc.